January 5, 2011

Australia’s Great Barrier Reef Facing Threat From Flooding

by ssavage

An expert said Wednesday that Australia's spectacular Great Barrier Reef is under threat from massive floods swamping the country's northeast, which are pouring harmful debris and sediment into the sea.

Michelle Devlin said that the full impact of the floods is not yet known, but the influx will stress the colorful corals.

"This does impact on the reef. It just impacts on the reef's resilience so you get very stressed corals, you get stressed sea grass," Devlin, a researcher at James Cook University in northern Queensland, told AFP.

"So let's just say that a big cyclone came along, knocked them all out. They might not recover so well because they are already very stressed."

She said that while the rivers have always poured into the reef, the floods were no longer bringing just rainwater, but also sediment, nutrients and pesticides.

"Top soil will run straight off into the water and that will come straight out into the Great Barrier Reef," Devlin told AFP.

"There's a lot of water around and already it would be influencing the reef," she said, describing the mixture of fresh, warm water, nutrient-heavy soil and pesticide run-offs as a harmful "cocktail" for the corals.

"There is just going to be this cocktail of water containing a lot of things that they (the corals) wouldn't necessarily have seen before. It is fresh, warm water and that will stress corals out as well."

She said flood plumes were visible near the coastal city of Rockhampton, where floods have virtually cut off the town of 75,000 and already stretched up to 25 miles offshore.

According to Devlin, as more floodwaters brought by weeks of torrential rains make their way to the coast, the dirty river water will pour into the reef for weeks, enabling the plume to extend for hundreds of miles.

Experts expect that the floodwaters will drift towards the Whitsunday Islands, which is a tourist hotspot at the center of the Great Barrier Reef Marine Park.

The plume is at the Keppel islands north of Rockhampton already, and Devlin said these would likely bear the brunt of the flood impact.

"I think the Keppels reefs... they will have quite high mortality," she said.

Devlin told AFP that the floods were some of the biggest in decades and it was too early to know what impact they would have on the Great Barrier Reef Marine Park.

However, she said that it was possible that sea grass beds could be wiped out in some areas while the additional nutrients in the water could allow the crown of thorns starfish to flourish.

"This is a really massive event," Devlin told AFP. "It has the potential to shift the food web, it has the potential to shift how the reef operates."

"But it is a really robust ecosystem," she said of the reef which teems with marine life and boasts hundreds of coral species.